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Finding the Fourth Proportional to 686.75, 947.70 and 392.09

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Solution

The fourth proportional to 686.75, 947.70 and 392.09 is: 541.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.75 : 947.70 = 392.09 : x
  2. Step 2: Convert to fraction form
    686.75/947.70 = 392.09/x
  3. Step 3: Cross multiply
    686.75x = 947.70 × 392.09
  4. Step 4: Simplify right side
    686.75x = 371,578.95
  5. Step 5: Solve for x
    x = 371,578.95/686.75
  6. Step 6: Final answer
    x = 541.07

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.